The present invention relates to a handy voice navigation system using a portable phone such as a cellular phone (hereinafter referred to as PDC) or a personal handy phone system (hereinafter referred to as PHS) that navigates a user of the portable phone to the desired destination upon receiving the voice band guidance from a base station that has received the information containing the present location and the desired destination reported by the user. More specifically the present invention relates to the voice navigation system of a portable phone that allows for an interactive process to specify the present location and the desired destination of the user and to navigate the user to the destination through synthetic voice.
The PHS service starting from July 1995 has urged the market to widely expand together with the conventional PDC services, expecting further increase in the number of users. The portable phone is expected to be used not only as a telephone but also as various kinds of applications.
Popularizing digitized interactive communication on the phone has enabled the phone itself to be integrated and formed into a logical circuit. Accordingly the digital portable phone is more suitable to transmit data compared with the portable phone of analogue type. The technology for connecting the digital portable phone to the information equipment such as a PC or a facsimile for transmitting either text data or image data has been widely spread.
In a first prior art disclosed in JP-A350733/1994, a portable phone is provided with a section for displaying map information.
When the user requires navigation to the base station controlling the service area where the user currently exists through the portable phone, the base station sends the user the map information covering the present service area and its periphery as the aid of navigation.
FIG. 6 is a view showing a construction of JP-A-261149/1994 as a second prior art. The second prior art of FIG. 6 forms a navigation system using a telephone network in which a navigation center is provided with a phone book database 103 correlated to a subscriber's phone number through a mobile communication channel 101 and a conventional public channel 102 for storing the subscriber's name, address and access point to the nearest traffic facilities.
When each user designates the subscriber's phone number as the destination to require navigation to the center 104 through the respective phone 101a-101c, 102a-102c, the center searches the phone book database 103 based on the phone numbers of both the user and the destination and supplies the user with the route leading to the destination, traffic information and the like.
FIG. 7 is a view explaining a construction of JP-A-A129894/1995 as a third prior art.
The third prior art of FIG. 7 comprises sensors Sa to Sn for detecting any damage of a vehicle and an on-board navigation system 201. The navigation system 201 comprises a built-in map database 202 that stores location data of a plurality of service centers. When the vehicle damage is detected, a route to the nearest service center is displayed on an image display device 204. Then navigation starts with the aid of the marking on the display and voice of a vocal guide device 200.
A cellular phone 203 can be connected to the navigation system 201 for communication with a control center supervising each service center through a telephone channel.
The control center stores a map database covering a wide area where a large number of service centers over a larger area have been registered. The voice data is further stored for aiding the voice guidance supplied by the navigation system 201.
The control center serves to support the navigation system 201 by indicating damage diagnosis, providing map information of the map database 202 or voice guidance of the voice guide device 200 even when no appropriate service center is located in the area that can be displayed by the navigation system 201.
Voice navigation using a conventional navigation system of the portable phone, however, has the following problems.
The first prior art requires the user to search the present location on the map by himself/herself. This also requires a display section on the portable phone for displaying the prepared map information. Such display section should have sufficient size and high resolution in order to allow the user to identify the present location with a single glance. Providing the aforementioned display section may increase the total weight and manufacturing cost, thus deteriorating handiness of the phone as well as failing to keep a reasonable price.
In the second prior art, the user's present location is reported to the base station as zone information of its control area. Therefore the base station cannot identify the present location as a specified spot. The navigation leading to the destination supplied by the base station becomes too rough for the user to be guided to the destination.
The third prior art has an assumption that, for example, a portable phone is combined with the on-board navigation system by which the user's present location is specified in advance. Therefore using only the portable phone cannot specify the present location, failing to have a report required for receiving the navigation service.
A navigation service using a Global Positioning System (GPS) has been well known as providing latitude and longitude of the present location on a global scale by calculating the time taken from reception of a wave signal sent from a plurality of geostationary satellites to reach thereof. The GPS used in an urban area with buildings standing close together is required to comprise a high sensitive antenna and a reception device, a logical circuit for calculating latitude and longitude based on the measured time or a built-in memory for storing map information covering a wide area. Providing the above-described components to the portable phone is not practical considering its excellent portability resulting from compact and light-weight characteristics.